Spatial Reuse Group Thresholds for 802.11ax Channel Access

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Solution Overview

Problem

In dense wireless communication environments, competing Access Points (APs) can cause unbalanced channel access and network security issues due to differing Clear Channel Assessment (CCA) levels, leading to reduced network capacity and performance.

Innovation Solution

Adding competing APs to the Spatial Reuse Group (SRG) and adjusting the SRG-based overlapping BSS power detect thresholds to equal or exceed the maximum threshold for Non-SRG APs, making deployed APs less sensitive to competing APs and improving channel access fairness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Spatial Reuse with different CCA levels for inter-BSS and intra-BSS frames is implemented, then network capacity and spectrum efficiency are improved, but unbalanced channel access and network security issues occur

Engineering Contradiction:
Improvenetwork capacityVSAvoidchannel access fairness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the CCA threshold parameter from a fixed value to a dynamic value that adapts based on whether the transmitting AP is in the SRG. Specifically, it uses a higher CCA threshold (OBSS_PD_SRG) for APs in the SRG and a lower CCA threshold (OBSS_PD_NonSRG) for APs not in the SRG, allowing flexible adjustment to achieve both high capacity and fair access

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the AP population into two distinct groups: APs in the Spatial Reuse Group (SRG) and APs not in the SRG. This segmentation allows different CCA threshold policies to be applied to different groups, enabling the system to simultaneously optimize for both network capacity (through SRG APs using higher thresholds) and channel access fairness (through Non-SRG APs using lower thresholds)

Inventive Principle:
Principle #1Segmentation

2Reliability

If deployed APs use lower CCA thresholds to detect competing APs, then channel access fairness is improved, but network capacity is reduced

Engineering Contradiction:
Improvechannel access fairnessVSAvoidnetwork capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies different CCA threshold qualities to different AP groups locally. APs in the SRG use a higher CCA threshold (OBSS_PD_SRG) that allows them to be more aggressive in channel access, while APs not in the SRG use a lower CCA threshold (OBSS_PD_NonSRG) that makes them more conservative. This local differentiation allows each group to operate with optimal thresholds for their role

Inventive Principle:
Principle #3Local quality

3Reliability

If competing APs are excluded from SRG, then network security is maintained, but interference management becomes less effective

Engineering Contradiction:
Improvenetwork securityVSAvoidinterference management efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent introduces the SRG as an intermediary mechanism that manages interference from competing APs. By adding competing APs to the SRG and assigning them specific CCA thresholds, the system mediates their interference impact, allowing controlled coexistence that improves overall interference management efficiency while maintaining security through proper threshold configuration

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3621336B1Enhanced channel access in 802.11ax using SRG for foreign aps
Publication Date: 2021.03.10 HEWLETT PACKARD ENTERPRISE DEV LP
  • EP3621336B1 patent drawingFigure 1
  • EP3621336B1 patent drawingFigure 2
  • EP3621336B1 patent drawingFigure 3~4

AI summary

Systems and methods for spatial reuse in a deployed wireless area network (WLAN) include identifying a plurality of competing APs of an external wireless network operating on a same channel as a deployed AP of a deployed wireless network; examining the received signal strength indicator (RSSI) of the identified plurality of competing APs of the external wireless network; filtering out selected one or more of the identified plurality of competing APs of the external wireless network based on their respective RSSIs to arrive at a filtered set of competing APs; and augmenting a spatial reuse group (SRG) of the deployed AP to include the APs in the filtered set of competing APs in the SRG.